change base image to distroless/static

Signed-off-by: Vilmos Martinek <vilmos.martinek@nokia.com>

Dockerfile

@@ -38,7 +38,7 @@ RUN --mount=target=. \
 
 # Produce the Function image. We use a very lightweight 'distroless' image that
 # does not include any of the build tools used in previous stages.
-FROM gcr.io/distroless/base-debian11 AS image
+FROM gcr.io/distroless/static-debian12:nonroot AS image
 WORKDIR /
 COPY --from=build /function /function
 EXPOSE 9443